1. Field of the Invention:
This invention relates to a mower comprising a frame which allows the mower to be hitched to a tractor and a mowing group connected to the frame by a joint with an axis directed substantially in the direction of advance. The mowing group is equipped with at least one cutting element and at least one rotor arranged close to the end of the mowing group where the latter is connected to said frame. The rotor extends in part at least above one part of the cutting element or elements and turns around an axis directed upward. The mower also comprises drive elements of the cutting element or elements and of the rotor comprising in particular a drive shaft made up by at least one part, penetrating in the rotor and turning substantially around the rotation axis of the rotor, and a bevel gear pair arranged at the upper end of the drive shaft. The mower further comprising a control element which allows for pivoting around the joint with an axis directed substantially in the direction of advance to bring the mowing group to a transport position in which the mowing group is directed upward.
2. Description of the Related Art:
FR-A-2 255 839 describes such a mower whose mowing group comprises a cutting bar equipped with six disks turning around axes directed upward. The disks extending at each end of the cutting bar are surmounted by a rotor. This known mower further comprises a frame which allows it to be hitched to a tractor. The mowing group is connected to this frame by means of a joint with an axis directed substantially in the direction of advance. For this purpose, the frame is equipped with a yoke to which is connected in an articulated manner a support element forming part of the mowing group. This support element comprises a foot extending substantially horizontally at the rear end of which is fastened a leg extending approximately vertically. The foot is fastened by its front end to the cutting bar and the leg is connected at its upper end to the frame by the joint with an axis directed substantially in the direction of advance. This support element extends in top view entirely behind the first disk. The disks and rotors of this known mower are driven in rotation by a drive shaft going through the rotor surmounting the first disk. This drive shaft comprises two parts connected to each other by an elastic coupling. At its lower part, the drive shaft is connected in rotation on one hand to the first disk and the rotor surmounting the latter, and on the other hand to a cylindrical gear housed in a cutting bar housing. This cylindrical gear transmits the movement to a cascade of other cylindrical gears also housed in the cutting bar housing and assuring the driving in rotation of the other disks and the other rotor. The drive shaft is itself driven in rotation by a shaft whose rotation axis is merged with the axis of the joint connecting the mowing group to the frame and by a bevel gear pair extending at the upper end of the drive shaft and connecting it in rotation to the shaft. This shaft is driven in rotation by the power takeoff of the tractor by a cardan shaft and a belt pulley device. This known mower also comprises a hydraulic cylinder fastened between the frame and the mowing group to bring the mowing group by pivoting around the joint to a transport position in which the mowing group extends upward.
This known mower exhibits the feature of having a mowing group whose overall width at ground level is equal to the width of the cutting. This is advantageous in several respects. Actually, during the first pass the mowing group does not bend the product to be harvested without cutting it. Further, during subsequent passes, it is not necessary to clear strips of ground wider than those necessary for the wheels of the tractor extending opposite the cutting bar. As there is no part of the mowing group which at ground level projects beyond the width of the cutting, the risks of packing due to hooking of the cut product to such a part is eliminated.
In transport, this known mower exhibits, however, the drawback of widely exceeding the overall width of the tractor. This is due in particular to the fact that the axis of the joint connecting the mowing group to the frame extends above the rotor surmounting the first disk, i.e. at a height relatively significant in relation to the ground. Thus, when the mowing group is pivoted into its transport position in which it extends substantially vertically, the mowing group extends laterally beyond the joint a distance equal to the value of said height. This therefore substantially increases the overall width of the tractor-mower unit and can pose problems for passing on narrow roads or through some farm entrance gates. This also causes visibility problems when driving. As the center of gravity of the mowing group is offset relatively laterally, the frame of the mower and the hitching device of the tractor are substantially stressed. In addition, the wheels of the tractor extending on the side opposite that where the mowing group extends, are eased substantially, which can pose stability problems for low-power tractors. The object of this invention is to solve this problem.